Hot air furnace attachment



Patented Feb. 20, 1940 artist I,

Carl Lengyel, Buffalo, N. Y. Application September 7, :1938, serial No. 228,810

6 Claims.

This invention relates to a hot air furnace and more particularly to means whereby a greater amount of the heat produced by the burning of fuel in the heating chamber is transferred to the air which is conducted to the building to be heated.

rlhe principal object of this invention is to provide an attachment for hot air furnaces whereby a greater, amount of heat is transferred from the burning fuel in the heating chamber to the air which passes from the air chamber to the rooms to be heated and which is so organized that the same can be conveniently applied to furnaces already installed and in use although the same can also be embodied advantageously in new fur- .naces Another object of this invention is to provide heat radiating means of this character which i can be readily appliedlto furnaces having air w 39 spaces of different widths and thus avoid the expense of making radiating means to fit furnaces v which vary in size. i

A further object of this invention-is to provide a heat radiating or transferring attachment'for furnaces which is of simple construction and capable of I being easily installed by unskilled workmen and wl'lich transfers a greater amountv of heat from the burning fuel to the air, thus effecting ,a corresponding `saving in the cost for 30 heating rooms.

In the accompanying drawing: h

Fig; 1 is a Vertical section of a hot airtfurnace equipped with these improvements.

Fig. 2 is a horizontal section taken on line 2-2, Fig. 1. V

Fig. 3 is a fragmentary horizontal section, on an enlarged scale, taken on line 3-3, Fig. 1.

Fig. 4 is a fragmenta'ry Vertical section, on an eniarged Scale, showing one form of meansl for I to Fig. 3 is a horizontal section taken on line 8-42. Fig. '7.v

Fig. E) is a fragmentary Vertical section showing spring means for pushing a radiating fin against the heating chamber of the furnace.

55 In the following description like reference drawing a radiating fin against the exterior of v characters denote corresponding parts in the I several figures of the drawing.

Although this invention is applicable to hot air furnaces of Avarious forms, that shown in the drawing as a satisfactory example for utilizingz this invention is constructed as follows:

.The numeral l represents' the tubular heatingchamber of the furnace in'fwhich the fuel is burned and which inv this case comprises a lower section or fire pot and a combustion `10 space or upper section 12 mounted on the lower section. Any suitable fuel may be burned in the heating chamber such as coal, `'woodg gas or oil, but the drawing shows the, furnace organized, for burning coal and the like whichv is supported 15 on a grate 13 which is arranged adiacent to lthe lower end of the heating chamber and mounted on an 'ash pit |4 which supports the lower section of the heating chamber. From the upper end of the heating chamberv the hot gases and products of combustion resulting from the burning fuel pass into ,a radiator, |5 mounted o n the upper section of the heating chamber and thence through the outlet IG thereof-to the chimney of the building tot the atmosphere.V

Although a gas tight connection may be`obtained between the several op'posing surfaces of the ash pit, heating chamber sections and the radiator, it is preferable to employ the means for this purpos'e which are now in common use and which consist of annular upwardly opening grooves or furrows 40, 4|, 42 formed respectively in upper edges of the ash pit and the heating chamber sections, providing thelower edgesof the lower and upper heating `chamber sections and the radiator with downwardly projecting tongues 43, 44, which engage respectively with the grooves 40, 4|, 42 and sealing theV joints between these grooves and tenons by means of cement 46, as shown in Figs. 1 and 4.' 40 Surrounding the ash pit, heating chamber andradiator is an enclosing casing preferably constructed of sheetv metal which forms between this casing and the ash pit, heatingV chamber and radiator, a'hot air -chamber through which air 5 passes from its lower end to the top thereof and then is discharged to the desired place. This casing may be of any suitable construction but that shown in the drawing is of the usual form and comprises a lower section i I'l resting on the I ing on the upper edge of the upper Casing section 2B, and a top 22 arranged above the radiator 15 and resting at its lower edge on the upper retaining ring 2| and provided with hot air delivery pipes 23 leading to the rooms to be heated.

The means embodying this invention for in- Creasing the heat transference from the heating Chamber to the air in the air Chamber are Constructed as follows:

The numeral 24 represents a plurality of upright radiating fins, preferably made of sheet metal, arranged in an annular row around the heating Chamber IB so that each fin is arranged radially or substantially radially relative to the Vertical axis of the furnace. These fins are preferably of such height that they extend from a position adjacent to the top of the ash pit to a position adjacent to the underside of the radiator and the same are of such width that the same extend from the heating Chamber close to the outer casing, thereby forming a plurality of upright fiues 25 through which the air to be heated fiows upwardly and is divided into a plurality of streams, a lower annular channel 26 which receives the air below the fins and distributes the same among the several fiues 25 and an upper dome 21 which receives the air from the upper ends of the several flues and conducts the same to the delivery pipes 23.V

v heating Chamber and as the air passes upwardly through the flues 25 in contact with the fins this heat is transferred from the latter to the air preparatory to delivering the same to the rooms to be heated. o

For the purpose of obtaining an intimate contact between the radiating fins and the exterior of the wall of the heating Chamber and thus se- Cure the maximum transference of heat, the inner edge of each'fin is provided with a plurality of contact wings 28 which are preferably arranged in two rows projecting laterally in opposite directions from the inner edge of the respective fin and engaging with the adjacent part of the external surface of the heating Chamber. The wings are preferably formed by providing the inner edge of the'sheet metal fin with a plurality of horizontal slits and bending the metal between successive pairs of slits alternately in opposite directions, as shown in Fig. 6. Due to the resilience of the sheet metal fins the wings thereof when moved inwardly into engagement with the heating Chamber wall, as shown in Fig. 5, will bear yieldingly against the latter and adapt the wings thereto so as to produce a firmmetallic contact with the heating Chamber wall and the wings and thus insure a maximum heat transference to the air passing through the air flues.

Various means may be employed for moving each of the fins toward the heating Chamber those shown in Figs. 1, 3 and 4 consisting of a plurality of hook bolts each of which has a radial body 29 passing through a bracket 35 on the inner part of the respective fin, a hook 3| 'at its inner end engaging with the adjacent part of one of the joint sealing grooves M, 4| or 42, andV a screw nut 32 working on the threaded outer part of the bolt body 29 and engaging with the outer side of the bracket 39. Upon tightening the units 32 of the several hool: bolts the fins will be moved inwardly and their contact'wings firmly engaged with the heating Chamber wall and thereby cause the heatto be eifectively transferred from this wall to the fins which latter in turn transmit the heat to the air moving upwardly in contact therewith.

The means just described for moving the fins inwardly toward the heating Chamber operate by a drawing action and are well suited for use in furnaces having Comparatively wide air chambers which permit of an installation of this Character. When however the air Chamber is comparatively narrow and only a limited amount of space is available for installing narrower fins it is preferable to employ fin mowfng means which operate by a pushing action.

In Figs. 7 and 8 a fin moving device of the last `mentioned Character is shown and consists of a bush bolt 33 passing with its threaded inner end through a bracket 34 on the fin and bearing with the head at its outer end against the inner side of an abutment forming part of the Casing, and a thrust screw nut 35 working on the thread of the bolt 33' and engaging the outer side of the braeket fill. Upon unscrewing the nut 35 from the bolt 33, the fin will be pushed inwardly and its contact wings engaged with the exterior of the heating Chamber wall.

Instead of using means for moving the fins vpositively toward the heating Chamber wall such as those shown in Figs. 1, 3,74, 6 and 7, means may be employed which exert a yielding pressure against the fins for producing Contact between the same and the heating Chamber wall, such for example, as the wishbone spring 35 which has its arms engaging respectively with a shoulder or flange 3'l on the outer edge of the respective fin M and an abutment formed by a part of the enclosing Casing, as shown inFig. 9. In this organization the spring exerts a Constant inward pressure onl the fin for maintaining contact bew tween the same and the heating Chamber Wall. The use of a spring for this purpose permits of some Variation of the width of the fins, the same can be installed quickly and conveniently and the 'same automatically takes up any slacl: or expansion which might occur during the installation or operation of the furnace.

In order to avoid the necessity of making the fins of an exact width to fit the width of the air space between the heating Chamber and the en- Closing casing and separate the air flues effectively from one another and also supporting the fins at their outer edges, the following means are provided.

The numeral 55 represents a plurality of upright supporting bars which are of L-shaped form in cross section and each mounted on the inner side of the enclosing Casing and overlapping the adjacent outer part of one of the fins soas to practically fonn a continuous web from the heating Chamber to the enclosing casing. Each of these supporting bars is secured at its lower end to the inner side of the lower casing section H by bolts 5! or otherwise but not Connected with the upper section 20 of the Case and its central part is provided with a notch 52 which receives the adjacent part of the intermediate retaining ring 19, as shown in Fig. 1. By means of this construction it is possible to install the several parts of this heat transferring means on a furnace already in use by merely removing the upper casing section 29 in order to gain access to the interior of the air Chamber 25 and then restoring this enclosing Casing section after the work is completed without disturbing any other parts of the furnace.

Each of the supporting bars is preferably conparts thereof and inserting i openings, such piercing nected with the Companion fin by one or, morelower edge portion folded upwardly to form a Aguide groove 54 which is slidab'ly engaged by the lower edge of the respective fin, as shown in Figs. 1 and 3. The bolts 53 are applied to the members M and`50 by piercing openings in corresponding these bolts in said a pointed tool inasmuch as the members 24 and 5B vare made of sheet metal.

It will be noted that in this inventionl each fin Comprises an inner section which is attached to the heating Chamber of the furnace and an outer section which is' attached to the 'enclosing Casing, which sections overlap each other and therefore permit of adjusting the width of each fin to suit the varying'widths of the air chambers of different furnaces without requiring any change in construction..

Moreover this improvement can be readily applied to hot air furnaces which are already installed and in use without members of the furnace, the addition of this invention to furnaces already installed being, conveniently effected by attaching one pair at a time of the Sections constituting a fin.

As awhole these heat transfer means are Comparatively vsimple in construction, the same .can be easily and Conveniently installed and the same permit of recoverin'g a substantial amount of the heat which otherwise would be lost and enables fuel to be used more advantageously and economically. i

I claim as my invention: v

l. A' hot .air furnace comprising a' heating Chamber, a casing' enclosing said heating chamber and forming an air Chamber therebetween, a plurality of upright radiating fins arranged in said air Chamber and engaging their inner e'dges with the exterior of said heating Chamber, a plurality of upright supportingbars secured to the inner side of said casing and each bar overlapping one of said fins,ian d means for guiding each radiating fin on the respective supporting bar preparatory to connecting each fin with its bar.

2. A hot air furnace comprising a heating Chamber, a casing enclosing said heating chamber and forming an air Chamber therebetween, a plurality of upright radiating fins arranged in said air Chamber and engaging their inner edges with the exterior of said heating Chamber, a plurality of upright supporting bars secured to the being readily effected byv tween each radiating fin and requiring dismantling I of any'of the hot air conduits or other mainv inner side of said casing and each bar overlapping one of' said fins, and means interposed between each radiating fin and the respective supporting bar for' pushing theflfin against said heatingchamber. i i

3. A hot air furnace comprising a heating Chamber, a casing enclosing said heati'ng chamber andtforming an air Chamber t erebetween, a pluralityV of upright radiating fins arranged in said air Chamber' and engagingtheir inner edges with the' exterior of said I rality of upright supporting bars'secured to the inner side of said casing and each bar overlapping one of'said fins, and means interposed bethe respective supportng Vbar for pushing the fin against heating chamber including a bolt bearing against said bar and a nut on said bolt bearing against said fin. i

4. A.` hot air furnace comprisingy a heating Chamber, a casing enclosing saidlheating chamber and forming an air Chamber therebetween, a plurality of upright radiating fins arrange'd in said air Chamber and engaging their inneredges with the exterior of said heating chamberjaplurality of upright supporting bars -secured to the heating chamber,v a plusaid inner side of said casing and each bar overlapping one of said fins, and' spring means interposed between each fin and the casing and operating to constantly press the respective fin against said heating chamber. j

5. A hot air furnace comprising a heating Chamber, a casing enclosing said heating Chamber andiforming an airchamber therebetween and including upper and lower sections and a retaining ring between the opposing edges of said Sections, a plurality of radiating fins arranged in said air Chamber and engaging said heating Chamber, and a plurality of supporting bars overlan-ping said fins and each bar having only its lower part connected With the inner side of said lower casing section while its upper part is disconnected from Vsaid upper casing section and the Central part of said bar being provided'with a notch which receives said retaining ring.

6. A hot air furnace comprising a ,heating Chamber, a casing enclosing the heating chamberand forming an air Chamber therebetween, and means for radiating heat from the heating Chamber to the air in said air Chamber including a plurality of radiating fins each. of which has an inner section secure'd to the outer side of the vheating Chamber and an outer section se'cured to the inner side' ofthe 'enclosing casing and said fin Sections having opposing edges which overlap and are adapted to be adjusted radially one relative tothe other and subsequently connected with each other.

C'ARL LENGYEL. 

